Optical communication techniques of processing time-series images (frames) captured by image sensors are known. For example, in Unexamined Japanese Patent Application Kokai Publication No. 2006-20294, assuming that outdoor illumination or the like is used as a transmission device emitting light modulated to information, a terminal device can acquire the information by photographing the transmission device with the camera installed therein and demodulating the received light.
Furthermore, in a recent scheme, instead of transmitting information directly, a transmission device emits light modulated according to information ID, a terminal device demodulates and decodes the received light to obtain the ID and sends the ID to the server or the like, and then the terminal device acquires the provided information corresponding to the ID from the server or the like.
In the prior art, the user can acquire the provided information by aligning the imaging direction of the camera provided to the terminal device to photograph a transmission device with the direction in which the transmission device is present.
However, if the user is not able to visually locate the transmission device, needless to say, the user cannot align the imaging direction with the direction in which the transmission device is present.